I based my numbers on this implementation: (http://bitcoin.biniok.net/gl.html) running chrome on a pentium 4. The rates are averages over 5 seconds.

I’ll show the math for WebWorkers since they have pretty decent support.

So lets say that we want 1 Million computers calculating hashes using webworkers at a rate of 13000 hashes/s. If we assume that each ad view results in 5 seconds of computing time then we can calculate the required number of ad views like: